/* $OpenBSD: lib_addch.c,v 1.6 2023/10/17 09:52:08 nicm Exp $ */

/****************************************************************************
 * Copyright 2019-2021,2022 Thomas E. Dickey                                *
 * Copyright 1998-2016,2017 Free Software Foundation, Inc.                  *
 *                                                                          *
 * Permission is hereby granted, free of charge, to any person obtaining a  *
 * copy of this software and associated documentation files (the            *
 * "Software"), to deal in the Software without restriction, including      *
 * without limitation the rights to use, copy, modify, merge, publish,      *
 * distribute, distribute with modifications, sublicense, and/or sell       *
 * copies of the Software, and to permit persons to whom the Software is    *
 * furnished to do so, subject to the following conditions:                 *
 *                                                                          *
 * The above copyright notice and this permission notice shall be included  *
 * in all copies or substantial portions of the Software.                   *
 *                                                                          *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
 * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
 *                                                                          *
 * Except as contained in this notice, the name(s) of the above copyright   *
 * holders shall not be used in advertising or otherwise to promote the     *
 * sale, use or other dealings in this Software without prior written       *
 * authorization.                                                           *
 ****************************************************************************/

/*
**      lib_addch.c
**
**      The routine waddch().
**
*/

#include <curses.priv.h>
#include <ctype.h>

MODULE_ID("$Id: lib_addch.c,v 1.6 2023/10/17 09:52:08 nicm Exp $")

static const NCURSES_CH_T blankchar = NewChar(BLANK_TEXT);

/*
 * Ugly microtweaking alert.  Everything from here to end of module is
 * likely to be speed-critical -- profiling data sure says it is!
 * Most of the important screen-painting functions are shells around
 * waddch().  So we make every effort to reduce function-call overhead
 * by inlining stuff, even at the cost of making wrapped copies for
 * export.  Also we supply some internal versions that don't call the
 * window sync hook, for use by string-put functions.
 */

/* Return bit mask for clearing color pair number if given ch has color */
#define COLOR_MASK(ch) (~(attr_t)(((ch) & A_COLOR) ? A_COLOR : 0))

static NCURSES_INLINE NCURSES_CH_T
render_char(WINDOW *win, NCURSES_CH_T ch)
/* compute a rendition of the given char correct for the current context */
{
    attr_t a = WINDOW_ATTRS(win);
    int pair = GetPair(ch);

    if (ISBLANK(ch)
        && AttrOf(ch) == A_NORMAL
        && pair == 0) {
        /* color/pair in attrs has precedence over bkgrnd */
        ch = win->_nc_bkgd;
        SetAttr(ch, a | AttrOf(win->_nc_bkgd));
        if ((pair = GET_WINDOW_PAIR(win)) == 0)
            pair = GetPair(win->_nc_bkgd);
        SetPair(ch, pair);
    } else {
        /* color in attrs has precedence over bkgrnd */
        a |= AttrOf(win->_nc_bkgd) & COLOR_MASK(a);
        /* color in ch has precedence */
        if (pair == 0) {
            if ((pair = GET_WINDOW_PAIR(win)) == 0)
                pair = GetPair(win->_nc_bkgd);
        }
        AddAttr(ch, (a & COLOR_MASK(AttrOf(ch))));
        SetPair(ch, pair);
    }

    TR(TRACE_VIRTPUT,
       ("render_char bkg %s (%d), attrs %s (%d) -> ch %s (%d)",
        _tracech_t2(1, CHREF(win->_nc_bkgd)),
        GetPair(win->_nc_bkgd),
        _traceattr(WINDOW_ATTRS(win)),
        GET_WINDOW_PAIR(win),
        _tracech_t2(3, CHREF(ch)),
        GetPair(ch)));

    return (ch);
}

NCURSES_EXPORT(NCURSES_CH_T)
_nc_render(WINDOW *win, NCURSES_CH_T ch)
/* make render_char() visible while still allowing us to inline it below */
{
    return render_char(win, ch);
}

/* check if position is legal; if not, return error */
#ifndef NDEBUG                  /* treat this like an assertion */
#define CHECK_POSITION(win, x, y) \
        if (y > win->_maxy \
         || x > win->_maxx \
         || y < 0 \
         || x < 0) { \
                TR(TRACE_VIRTPUT, ("Alert! Win=%p _curx = %d, _cury = %d " \
                                   "(_maxx = %d, _maxy = %d)", win, x, y, \
                                   win->_maxx, win->_maxy)); \
                return(ERR); \
        }
#else
#define CHECK_POSITION(win, x, y)       /* nothing */
#endif

static bool
newline_forces_scroll(WINDOW *win, NCURSES_SIZE_T *ypos)
{
    bool result = FALSE;

    if (*ypos >= win->_regtop && *ypos <= win->_regbottom) {
        if (*ypos == win->_regbottom) {
            *ypos = win->_regbottom;
            result = TRUE;
        } else if (*ypos < win->_maxy) {
            *ypos = (NCURSES_SIZE_T) (*ypos + 1);
        }
    } else if (*ypos < win->_maxy) {
        *ypos = (NCURSES_SIZE_T) (*ypos + 1);
    }
    return result;
}

/*
 * The _WRAPPED flag is useful only for telling an application that we've just
 * wrapped the cursor.  We don't do anything with this flag except set it when
 * wrapping, and clear it whenever we move the cursor.  If we try to wrap at
 * the lower-right corner of a window, we cannot move the cursor (since that
 * wouldn't be legal).  So we return an error (which is what SVr4 does).
 * Unlike SVr4, we can successfully add a character to the lower-right corner
 * (Solaris 2.6 does this also, however).
 */
static int
wrap_to_next_line(WINDOW *win)
{
    win->_flags |= _WRAPPED;
    if (newline_forces_scroll(win, &(win->_cury))) {
        win->_curx = win->_maxx;
        if (!win->_scroll)
            return (ERR);
        scroll(win);
    }
    win->_curx = 0;
    return (OK);
}

#if USE_WIDEC_SUPPORT
static int waddch_literal(WINDOW *, NCURSES_CH_T);
/*
 * Fill the given number of cells with blanks using the current background
 * rendition.  This saves/restores the current x-position.
 */
static void
fill_cells(WINDOW *win, int count)
{
    NCURSES_CH_T blank = blankchar;
    int save_x = win->_curx;
    int save_y = win->_cury;

    while (count-- > 0) {
        if (waddch_literal(win, blank) == ERR)
            break;
    }
    win->_curx = (NCURSES_SIZE_T) save_x;
    win->_cury = (NCURSES_SIZE_T) save_y;
}
#endif

/*
 * Build up the bytes for a multibyte character, returning the length when
 * complete (a positive number), -1 for error and -2 for incomplete.
 */
#if USE_WIDEC_SUPPORT
NCURSES_EXPORT(int)
_nc_build_wch(WINDOW *win, ARG_CH_T ch)
{
    char *buffer = WINDOW_EXT(win, addch_work);
    int len;
    int x = win->_curx;
    int y = win->_cury;
    mbstate_t state;
    wchar_t result;

    if ((WINDOW_EXT(win, addch_used) != 0) &&
        (WINDOW_EXT(win, addch_x) != x ||
         WINDOW_EXT(win, addch_y) != y)) {
        /* discard the incomplete multibyte character */
        WINDOW_EXT(win, addch_used) = 0;
        TR(TRACE_VIRTPUT,
           ("Alert discarded multibyte on move (%d,%d) -> (%d,%d)",
            WINDOW_EXT(win, addch_y), WINDOW_EXT(win, addch_x),
            y, x));
    }
    WINDOW_EXT(win, addch_x) = x;
    WINDOW_EXT(win, addch_y) = y;

    /*
     * If the background character is a wide-character, that may interfere with
     * processing multibyte characters in this function.
     */
    if (!is8bits(CharOf(CHDEREF(ch)))) {
        if (WINDOW_EXT(win, addch_used) != 0) {
            /* discard the incomplete multibyte character */
            WINDOW_EXT(win, addch_used) = 0;
            TR(TRACE_VIRTPUT,
               ("Alert discarded incomplete multibyte"));
        }
        return 1;
    }

    init_mb(state);
    buffer[WINDOW_EXT(win, addch_used)] = (char) CharOf(CHDEREF(ch));
    WINDOW_EXT(win, addch_used) += 1;
    buffer[WINDOW_EXT(win, addch_used)] = '\0';
    if ((len = (int) mbrtowc(&result,
                             buffer,
                             (size_t) WINDOW_EXT(win, addch_used),
                             &state)) > 0) {
        attr_t attrs = AttrOf(CHDEREF(ch));
        if_EXT_COLORS(int pair = GetPair(CHDEREF(ch)));
        SetChar(CHDEREF(ch), result, attrs);
        if_EXT_COLORS(SetPair(CHDEREF(ch), pair));
        WINDOW_EXT(win, addch_used) = 0;
    } else if (len == -1) {
        /*
         * An error occurred.  We could either discard everything,
         * or assume that the error was in the previous input.
         * Try the latter.
         */
        TR(TRACE_VIRTPUT, ("Alert! mbrtowc returns error"));
        /* handle this with unctrl() */
        WINDOW_EXT(win, addch_used) = 0;
    }
    return len;
}
#endif /* USE_WIDEC_SUPPORT */

static
#if !USE_WIDEC_SUPPORT          /* cannot be inline if it is recursive */
NCURSES_INLINE
#endif
int
waddch_literal(WINDOW *win, NCURSES_CH_T ch)
{
    int x;
    int y;
    struct ldat *line;

    x = win->_curx;
    y = win->_cury;

    CHECK_POSITION(win, x, y);

    ch = render_char(win, ch);

    line = win->_line + y;

    CHANGED_CELL(line, x);

    /*
     * Build up multibyte characters until we have a wide-character.
     */
#if NCURSES_SP_FUNCS
#define DeriveSP() SCREEN *sp = _nc_screen_of(win);
#else
#define DeriveSP()              /*nothing */
#endif
    if_WIDEC({
        DeriveSP();
        if (WINDOW_EXT(win, addch_used) != 0 || !Charable(ch)) {
            int len = _nc_build_wch(win, CHREF(ch));

            if (len >= -1) {
                attr_t attr = AttrOf(ch);

                /* handle EILSEQ (i.e., when len >= -1) */
                if (len == -1 && is8bits(CharOf(ch))) {
                    const char *s = NCURSES_SP_NAME(unctrl)
                      (NCURSES_SP_ARGx (chtype) CharOf(ch));

                    if (s[1] != '\0') {
                        int rc = OK;
                        while (*s != '\0') {
                            rc = waddch(win, UChar(*s) | attr);
                            if (rc != OK)
                                break;
                            ++s;
                        }
                        return rc;
                    }
                }
                if (len == -1)
                    return waddch(win, ' ' | attr);
            } else {
                return OK;
            }
        }
    });

    /*
     * Non-spacing characters are added to the current cell.
     *
     * Spacing characters that are wider than one column require some display
     * adjustments.
     */
    if_WIDEC({
        int len = _nc_wacs_width(CharOf(ch));
        int i;
        int j;

        if (len == 0) {         /* non-spacing */
            if ((x > 0 && y >= 0)
                || (win->_maxx >= 0 && win->_cury >= 1)) {
                NCURSES_CH_T *dst;
                wchar_t *chars;
                if (x > 0 && y >= 0) {
                    for (j = x - 1; j >= 0; --j) {
                        if (!isWidecExt(win->_line[y].text[j])) {
                            win->_curx = (NCURSES_SIZE_T) j;
                            break;
                        }
                    }
                    dst = &(win->_line[y].text[j]);
                } else {
                    dst = &(win->_line[y - 1].text[win->_maxx]);
                }
                chars = dst->chars;
                for (i = 0; i < CCHARW_MAX; ++i) {
                    if (chars[i] == 0) {
                        TR(TRACE_VIRTPUT,
                           ("adding non-spacing %s (level %d)",
                            _tracech_t(CHREF(ch)), i));
                        chars[i] = CharOf(ch);
                        break;
                    }
                }
            }
            goto testwrapping;
        } else if (len > 1) {   /* multi-column characters */
            /*
             * Check if the character will fit on the current line.  If it does
             * not fit, fill in the remainder of the line with blanks.  and
             * move to the next line.
             */
            if (len > win->_maxx + 1) {
                TR(TRACE_VIRTPUT, ("character will not fit"));
                return ERR;
            } else if (x + len > win->_maxx + 1) {
                int count = win->_maxx + 1 - x;
                TR(TRACE_VIRTPUT, ("fill %d remaining cells", count));
                fill_cells(win, count);
                if (wrap_to_next_line(win) == ERR)
                    return ERR;
                x = win->_curx;
                y = win->_cury;
                CHECK_POSITION(win, x, y);
                line = win->_line + y;
            }
            /*
             * Check for cells which are orphaned by adding this character, set
             * those to blanks.
             *
             * FIXME: this actually could fill j-i cells, more complicated to
             * setup though.
             */
            for (i = 0; i < len; ++i) {
                if (isWidecBase(win->_line[y].text[x + i])) {
                    break;
                } else if (isWidecExt(win->_line[y].text[x + i])) {
                    for (j = i; x + j <= win->_maxx; ++j) {
                        if (!isWidecExt(win->_line[y].text[x + j])) {
                            TR(TRACE_VIRTPUT, ("fill %d orphan cells", j));
                            fill_cells(win, j);
                            break;
                        }
                    }
                    break;
                }
            }
            /*
             * Finally, add the cells for this character.
             */
            for (i = 0; i < len; ++i) {
                NCURSES_CH_T value = ch;
                SetWidecExt(value, i);
                TR(TRACE_VIRTPUT, ("multicolumn %d:%d (%d,%d)",
                                   i + 1, len,
                                   win->_begy + y, win->_begx + x));
                line->text[x] = value;
                CHANGED_CELL(line, x);
                ++x;
            }
            goto testwrapping;
        }
    });

    /*
     * Single-column characters.
     */
    line->text[x++] = ch;
    /*
     * This label is used only for wide-characters.
     */
    if_WIDEC(
  testwrapping:
    );

    TR(TRACE_VIRTPUT, ("cell (%d, %d..%d) = %s",
                       win->_cury, win->_curx, x - 1,
                       _tracech_t(CHREF(line->text[win->_curx]))));

    if (x > win->_maxx) {
        return wrap_to_next_line(win);
    }
    win->_curx = (NCURSES_SIZE_T) x;
    return OK;
}

static NCURSES_INLINE int
waddch_nosync(WINDOW *win, const NCURSES_CH_T ch)
/* the workhorse function -- add a character to the given window */
{
    NCURSES_SIZE_T x, y;
    chtype t = (chtype) CharOf(ch);
#if USE_WIDEC_SUPPORT || NCURSES_SP_FUNCS || USE_REENTRANT
    SCREEN *sp = _nc_screen_of(win);
#endif
    const char *s = NCURSES_SP_NAME(unctrl) (NCURSES_SP_ARGx t);
    int tabsize = 8;

    /*
     * If we are using the alternate character set, forget about locale.
     * Otherwise, if unctrl() returns a single-character or the locale
     * claims the code is printable (and not also a control character),
     * treat it that way.
     */
    if ((AttrOf(ch) & A_ALTCHARSET)
        || (
#if USE_WIDEC_SUPPORT
               (sp != 0 && sp->_legacy_coding) &&
#endif
               s[1] == 0
        )
        || (
               (isprint((int) t) && !iscntrl((int) t))
#if USE_WIDEC_SUPPORT
               || ((sp == 0 || !sp->_legacy_coding) &&
                   (WINDOW_EXT(win, addch_used)
                    || !_nc_is_charable(CharOf(ch))))
#endif
        )) {
        return waddch_literal(win, ch);
    }

    /*
     * Handle carriage control and other codes that are not printable, or are
     * known to expand to more than one character according to unctrl().
     */
    x = win->_curx;
    y = win->_cury;
    CHECK_POSITION(win, x, y);

    switch (t) {
    case '\t':
#if USE_REENTRANT
        tabsize = *ptrTabsize(sp);
#else
        tabsize = TABSIZE;
#endif
        x = (NCURSES_SIZE_T) (x + (tabsize - (x % tabsize)));
        /*
         * Space-fill the tab on the bottom line so that we'll get the
         * "correct" cursor position.
         */
        if ((!win->_scroll && (y == win->_regbottom))
            || (x <= win->_maxx)) {
            NCURSES_CH_T blank = blankchar;
            AddAttr(blank, AttrOf(ch));
            while (win->_curx < x) {
                if (waddch_literal(win, blank) == ERR)
                    return (ERR);
            }
            break;
        } else {
            wclrtoeol(win);
            win->_flags |= _WRAPPED;
            if (newline_forces_scroll(win, &y)) {
                x = win->_maxx;
                if (win->_scroll) {
                    scroll(win);
                    x = 0;
                }
            } else {
                x = 0;
            }
        }
        break;
    case '\n':
        wclrtoeol(win);
        if (newline_forces_scroll(win, &y)) {
            if (win->_scroll)
                scroll(win);
            else
                return (ERR);
        }
        /* FALLTHRU */
    case '\r':
        x = 0;
        win->_flags &= ~_WRAPPED;
        break;
    case '\b':
        if (x == 0)
            return (OK);
        x--;
        win->_flags &= ~_WRAPPED;
        break;
    default:
        while (*s) {
            NCURSES_CH_T sch;
            SetChar(sch, UChar(*s++), AttrOf(ch));
            if_EXT_COLORS(SetPair(sch, GetPair(ch)));
            if (waddch_literal(win, sch) == ERR)
                return ERR;
        }
        return (OK);
    }

    win->_curx = x;
    win->_cury = y;

    return (OK);
}

NCURSES_EXPORT(int)
_nc_waddch_nosync(WINDOW *win, const NCURSES_CH_T c)
/* export copy of waddch_nosync() so the string-put functions can use it */
{
    return (waddch_nosync(win, c));
}

/*
 * The versions below call _nc_synchook().  We wanted to avoid this in the
 * version exported for string puts; they'll call _nc_synchook once at end
 * of run.
 */

/* These are actual entry points */

NCURSES_EXPORT(int)
waddch(WINDOW *win, const chtype ch)
{
    int code = ERR;
    NCURSES_CH_T wch;
    SetChar2(wch, ch);

    TR(TRACE_VIRTPUT | TRACE_CCALLS, (T_CALLED("waddch(%p, %s)"), (void *) win,
                                      _tracechtype(ch)));

    if (win && (waddch_nosync(win, wch) != ERR)) {
        _nc_synchook(win);
        code = OK;
    }

    TR(TRACE_VIRTPUT | TRACE_CCALLS, (T_RETURN("%d"), code));
    return (code);
}

NCURSES_EXPORT(int)
wechochar(WINDOW *win, const chtype ch)
{
    int code = ERR;
    NCURSES_CH_T wch;
    SetChar2(wch, ch);

    TR(TRACE_VIRTPUT | TRACE_CCALLS, (T_CALLED("wechochar(%p, %s)"),
                                      (void *) win,
                                      _tracechtype(ch)));

    if (win && (waddch_nosync(win, wch) != ERR)) {
        bool save_immed = win->_immed;
        win->_immed = TRUE;
        _nc_synchook(win);
        win->_immed = save_immed;
        code = OK;
    }
    TR(TRACE_VIRTPUT | TRACE_CCALLS, (T_RETURN("%d"), code));
    return (code);
}